There are numerous obstacles that prohibit wide acceptance of video teleconferencing (videoconferencing). One of the key technical obstacles is the high bandwidth consumption of video streams. In a multi-site configuration, this bandwidth demand becomes most prominent at central locations such as meeting rooms to which many remote users connect. For example, in a configuration where 10 users receive video and audio feeds from a given meeting room, the video conferencing equipment at that room may have to stream 30 individual video and audio streams to remote users from (typically) three different cameras. With each stream consuming bandwidth of more than 1 Mbps, the total bandwidth use can thereby peak to more than 30 Mbps.
Multicast transmission of IP (Internet Protocol) video packets is one of the most effective solutions to the video and audio distribution problem described above. However, multicasting is only enabled and used in tightly controlled enterprise and service provider networks such as the ones used for IPTV (Internet Protocol Television) services. Other uses of multicasting are also provided via dedicated backbone multicast networks, but otherwise, multicasting capabilities are not typically available on public networks that cross multiple domains.
The majority of the existing videoconferencing systems attempt to tackle this problem by providing a high-end server with large processing power and high network input/output capabilities. These servers are typically located in environmentally controlled facilities. Obvious drawbacks of this approach include high capital and operations cost, loss of security in the case of hosted and service-based configurations where the server is located outside the company facilities, and increased but still limited capability to support a large number of videoconferencing users. In addition, these existing approaches offer limited scalability to very large teleconferencing applications.